Please see attached photo with website.
Perhaps contacting a vet that specializes in poultry to answer your question. I read “pull” and “bleed” and I think pain to the bird.Its an "outgrowth of the legbone" but doesnt really mean it is a bone or attached to the bone. It's just a matter of semantics, you both are correct.
But I am still looking for instructions or confirmation that pulling a spur is indeed a non-cruel way to cut spurs. When I cut them I just let them bleed. I really want to know more about how pulling them effects them vs cutting.